The present invention relates to a novel apparatus and method to shut down pipelines. With the help of the invention, a massively leaking pipeline, generally a gas and/or oil drilling pipe, sewer, process industry pipe, or natural gas pipe or other such pipe is shut down in a manner which guarantees a tight plugging.
In the methods known, the pipeline is shut down by drilling a hole through the pipe from the side, installing a plug in the hole; or, normally, the valves at the end(s) of the pipe or elsewhere in the pipe are closed. The factors of uncertainty in the functioning of such a method to shut down a pipe are the breaking of the valve in case of a disaster or poor durability of the seam of the plug due to the prevalence of long-term stress, in general pressure, impact pressure, or other such stress.
With the help of the invention, the plugging of a pipeline to be shut down and mainly the seam between the plug and the pipeline can be sealed effectively. The seam in question can be made tight when the diameter of the hole to be drilled through is as close to the same size as possible with the diameter of the plug to be installed. According to this invention, this aim can be achieved in the following manner: from the start of the plugging process, i.e., drilling, a coolant, preferably liquid nitrogen, carbonic acid, or other such substance, is fed through parts of the apparatus, such as the drill and/or plug cylinder or a combination thereof, into the pipeline always essentially to the point where the plug cylinder has advanced to the determined depth and been installed in place. The cool liquid, or the gas evaporating from it, cools the parts being drilled through whereupon the holes drilled into the pipeline are smaller than those drilled without cooling. After stopping the feeding of the coolant, the plug cylinders located in the drilling seams expand as a result of an elevation in the temperature, especially in gas and/or oil drilling pipes or in pipes used in process industry, thereby forming a tight plug in the drilling seam created by the drill penetrating the pipeline. At the same time, the coolant suppresses any possible oil or gas fire, etc. when gushing out of the leakage point in the pipeline, i.e., the fire pocket. After the apparatus has performed the shutting down of the pipe, the channel inside the plug cylinder can be filled with a material freely expanding the air, preferably with polyurethane or any other such material, in order to increase the sealing capacity of the plug. To stop a massive oil leak in two or more nested gas and/or oil drilling pipes, the embodiment of the apparatus and method used is as follows: the shutting down is started from the innermost pipe with the smallest diameter and thickest wall, thereafter advancing to a bigger pipe with the diameter next in size and so on. The pipe with the smallest diameter is shut down at a lower point than the bigger pipe next in size, and so on. This order from the bottom upwards and from the smallest one to a bigger one produces tight plugs and durable seams due to the following:
1. The pipe with the smallest diameter reaches deepest down into the ground whereupon the oil coming from there discharges with the highest pressure and is a thicker and stiffer liquid. If this liquid discharges into the flow space of the pipes with a larger diameter and thinner walls, the walls of the pipes in questions cannot resist this pressurexe2x80x94at least not after the said pipe is shut downxe2x80x94and they break.
2. If a pipe with a larger diameter is shut down by drilling a hole through it when a pipe/pipes smaller than it is/are not yet shut down, the bottom ends of the pipes with a smaller diameter below it come loose and fall off their place. Once again, there will be a massive oil leak from the flow space of the pipe(s) with a smaller diameter into the flow space of the bigger pipe and the walls of the pipe in question break.